System Architecture

System Architecture

The Catalyst architecture is designed from the ground up as a combination hardware and software solution to provide ease of use, system flexibility, and functionality along with easy system maintenance. It is a distributed and robust architecture with no central switch that is built to minimize the impact of a failure of any particular system component. The system consists of advanced radio gateway servers and client user interface software which interfaces with the gateways through a local or wide area network (WAN).

Overview of Operation

Voice and control messages from standards-based and proprietary radio systems are received via wireline interfaces or by donor radios and are translated by Catalyst Gateways into UDP packets (voice) and TCP/IP packets (control). These IP packets are then fed to an IP network and can be controlled by an end user (Dispatcher, etc.) using IP|Console™, Propulsion™, Desktop Dispatch™, or IntelliLink™. A multitude of Catalyst gateways are available to support the wide variety of standards-based and proprietary land mobile radio networks available in the market, such as P25, DMR, SmartNet™, EDACS™, LTR, and conventional, as well as PTT over LTE. There is no limit to the number or type of Catalyst gateways that can be placed in a Catalyst system, and there are no limitations to the physical distance between gateway locations or console locations.

Gateway Technology

There are two types of Catalyst Gateways, wireline and wireless.  The wireline radio gateways connect directly into the Radio Frequency Sub-System (RFSS) or base station via a single Ethernet connection for voice and control.  There are also wireline gateways for both analog and digital connections to the PSTN, PBXs and other SIP devices. Most wireless gateways employ two connections to the donor radio or base station — a 2 or 4 wire audio connection which converts received audio to UDP packets; and a control and data connection which is converted to TCP/IP packets. UDP is an effective and bandwidth efficient method of sending voice; however, TCP/IP is required for critical communications. When a command is issued to a Catalyst gateway to perform a function such as to change systems or channels, the gateway provides feedback to the system to ensure the state change has been completed. Other wireless gateways use a single digital connection for both voice and control; they also use UDP and TCP as described above.

Catalyst’s advanced gateway technology also ensures successful communications by knowing when the radio system has assigned a channel. If there is no channel available, the gateway can automatically buffer the audio and wait to begin transmission until the audio can be safely routed. Competitive systems can lose portions of transmissions, which is unacceptable in critical communications. Advanced functions are radio dependent; contact Catalyst for details on your specific implementation.

How Radio Control over IP Works

Additional Benefits of Catalyst’s Advanced Gateway Technology:

Full radio control provides for valuable features such as automatic change of channels or talk groups. If a radio is tuned to a channel or talk group which is different from what is intended for a transmission, the gateway will automatically buffer the audio while it automatically retunes the radio channel to begin appropriate transmission for interoperability calls.

Catalyst has successfully worked with many radio manufacturers to provide intelligent interfaces for advanced functionality.

  • SIP (Session Initiation Protocol) Interface for Telephony and other applications.
  • Simple to complex radio patches can be created with a few clicks of a mouse.
  • Patches may be channel or talk-group specific, may be uni- or bi-directional, and may involve multiple gateways at different locations.
  • Catalyst provides the Dispatcher critical parameters including unit ID and emergency indication.
  • Each gateway stores and records call history and audio files for playback with the optional voice recording module.
  • Alerts and pages are stored on the gateway and pushed out to the radio network upon request from any dispatch position.

Radio Systems Supported

  • Project 25 (P25), Console Sub-System Interface (CSSI), Digital Fixed Station Interface (DFSI), Common Air Interface (CAI, using control stations)
  • Digital Mobile Radio (DMR), Application Interface Specification (AIS), Air Interface Protocol (AIP)
  • NXDN
  • SmartNet™
  • EDACS™
  • LTR
  • Push-To-Talk over LTE
  • Conventional with MDC 1200 and more…

In addition to our pioneering radio gateway servers for wireless connections like IP Radio™ and IP Fleet™ and our CSSI, DFSI, and AIS wireline gateways, we also offer two additional server types which can be added to a system for additional functionality: Administrative Server and SIP Server.

Administrative Server is an application that can be run on any computer connected to the WAN that stores items such as the layouts used by dispatchers in IP|Console™, in a central location. When enabled, a dispatcher can sit down at any console, log in, and retrieve their specific layouts, no matter which position they pick in the dispatch center—and thus removing the need to assign particular physical consoles to dispatchers. It also gives administrators control over which layouts are available to whom.

EDACS™ is a trademark of Harris, Inc. and SmartNet™ is a trademark of Motorola, Inc. IP Radio, IP Fleet, IntelliLink, and IP Link are trademarks of Catalyst Communications Technologies, Inc.


Radio Control over IP (RCoIP) provides the essential signaling and management for voice messages required for Critical Communications and is a step up from the more limited Radio over IP (RoIP). Catalyst pioneered this approach and built it for the Land Mobile Radio industry from the ground up. RCoIP is designed so that essential messages get through by using confirmed signaling, not best effort signaling. With nearly two decades of experience deploying mission critical voice solutions, Catalyst has created unique call flow management technology and has partnered with the major radio manufacturers to provide real-time feedback from your radio system to maximize call delivery.

Catalyst RCoIP provides unique but essential information required by Critical Communications users such as Emergency, Unit ID, and channel availability. It allows dispatchers to choose from hundreds of channels on each Gateway and control functions like scan and encryption. Through our superior technology, partnerships with radio manufacturers, and outstanding customer support, Catalyst solutions provide Public Safety, Utility, Federal, Education, and other agencies with peace of mind.


Notice anything different? We'll be updating everyone this month with news about what is going down at IWCE in Orlando March 5-8. We're excited to tell you we'll have a major new product announcement. Here's a spoiler alert! Can you guess???